Observer variability of absolute and relative thrombus density measurements in patients with acute ischemic stroke

Introduction: Thrombus density may be a predictor for acute ischemic stroke treatment success. However, only limited data on observer variability for thrombus density measurements exist. This study assesses the variability and bias of four common thrombus density measurement methods by expert and non-expert observers. Methods: For 132 consecutive patients with acute ischemic stroke, three experts and two trained observers determined thrombus density by placing three standardized regions of interest (ROIs) in the thrombus and corresponding contralateral arterial segment. Subsequently, absolute and relative thrombus densities were determined using either one or three ROIs. Intraclass correlation coefficient (ICC) was determined, and Bland–Altman analysis was performed to evaluate interobserver and intermethod agreement. Accuracy of the trained observer was evaluated with a reference expert observer using the same statistical analysis. Results: The highest interobserver agreement was obtained for absolute thrombus measurements using three ROIs (ICCs ranging from 0.54 to 0.91). In general, interobserver agreement was lower for relative measurements, and for using one instead of three ROIs. Interobserver agreement of trained non-experts and experts was similar. Accuracy of the trained observer measurements was comparable to the expert interobserver agreement and was better for absolute measurements and with three ROIs. The agreement between the one ROI and three ROI methods was good. Conclusion: Absolute thrombus density measurement has superior interobserver agreement compared to relative density measurement. Interobserver variation is smaller when multiple ROIs are used. Trained non-expert observers can accurately and reproducibly assess absolute thrombus densities using three ROIs

Performance Measurement in Military Operations: Information versus Incentives

We explore the impact of success measurement on military organizations. In particular, we develop a model to understand how imperfect measures of success may have deleterious externalities by creating unintended incentive structures for an agent. We show that the informational properties of the measurements are based on how the measure di¤ers from operational success while the incentive properties of the measurement are based on di¤er- ences in the marginal sensitivity of both the measure and operational success. Further, we show that undervaluing incentive properties of measurement will lead to systematic posi- tive bias of information. We use the examples of the Second World War and the Vietnam War to illustrate variation in the di¢ culty of measurement from conventional warfare to counterinsurgency. Finally, we discuss the relevance of our analysis to the current con ict in Afghanistan. Blanken

Unpacking the Various Meanings of Redundancy: From Refining the Concept to Military Planning

The article of record as published may be found at http://dx.doi.org/10.1080/14751798.2012.730721The authors engage in the debate over waste in military force structure planning by rigorously deconstructing the concept of “redundancy.” First, a typology of redundancy is constructed that provides a common framework for identifying variety among redundant structures. These are labeled “true redundancy,” “expanded capacity,” “portfolio diversification,” and “mission overlap.” Further, a number of mechanisms are identified that produce these types of structures, and show the conditions under which planners may utilize redundant structure in the search for optimization. In sum, the article provides refined concepts for analysts and planners to identify when redundancy is deleterious or beneficial

Performance Measurement in Military Operations: Information versus Incentives

accepted for publication in Defence and Peace EconomicsWe explore the impact of strategic assessment efforts on military organizations at war. To do so, we construct a model to explore the impact of a principal’s choice among imperfect performance metrics for a military operation. In doing so, the principal must consider both the incentivizing and informational properties of the metric. We show the conditions under which uncertainty regarding the nature of the agent, as well as uncertainty regarding the operational environment, drives a metric choice that induces pathological behavior from the agent. More specifically, a poor metric choice can create an overly optimistic assessment and end up prolonging the conflict. We illustrate the model’s insights in the cases of the Second World War and the Vietnam War

Reconciling strategic studies... with itself: a common framework for choosing among strategies

A previous draft was presented at the 2009 ISSS/ISAC Conference held in Monterey, CA.I identify three distinct, and seemingly irreconcilable, schools of thought within the strategic studies literature. One which searches for “universal principles of war”, a second, “context dependent”, approach that seeks to embed each instance of warfare within its concurrent social, political, technological milieu, and, finally a “paradoxical logic” school, which equates strategy with the generation of uncertainty. I offer some intuitive concepts from non-cooperative game theory to develop a “dominate-mix” approach to strategy choice. In doing so, I help to reconcile these disparate approaches and provide a simple framework to assist researchers in framing military decisions as well as to assist planners in choosing among strategies

The Strategic Utility of Small-State Special Operations Forces (SOF) as Information Collectors to Support National Decision-Making

Defense Analysis Poste

Arming the Peace: Foreign Security Assistance and Human Rights Conditions in Post-Conflict Countries

The article of record as published may be found athttps://doi.org/10.1080/10242694.2018.1558388What are the effects of foreign security assistance on the quality of the peace in post-conflict countries? Despite the stakes, and the tremendous amount of weaponry and other forms of foreign military aid flowing to governments of post-conflict countries, the academic literature provides little guidance as to what effects policymakers and practitioners should expect from this type of aid. Military assistance provided to the govern- ment of a country emerging from the turmoil of civil war could enable the state to establish a monopoly on the legitimate use of force, leading to a more durable peace and greater human security. However, we contend that significant flows of military aid and weapons from foreign governments may encourage regimes to adopt more repressive approaches to governance. We investigate the impact of security assis- tance on human rights conditions after 171 internal armed conflicts that ended between 1956 and 2012 using a novel measure of military aid and an instrumented measure of weapons transfers. We find strong evidence that both military aid and arms transfers to post-conflict governments increase state repression

SLOWING DOWN TO KEEP THE LEAD IN MILITARY TECHNOLOGY

We develop a model of military technology competition among states. States can choose to introduce new military technology, mimic rivals' level of technology, or withdraw from the contest. States can choose to implement any level of technology within their current feasible technologies. We find that states with significant technological leads should sometimes withhold new technologies, only strategically releasing them to trump rivals' efforts. We develop the model by refining Admiral Jackie Fisher's roughly articulated concept of 'plunging'. We then use this refined argument to reanalyze the case of naval rivalries among European powers between the Crimean War and the First World War. Finally, we conclude by discussing the model's implications for current US military force structure planning.technology diffusion, quolitative arms races, conventional force structure planning, weapons development,